This invention relates in general to an interface structure for selectively connecting a plurality of internal electrical conductors contained within an electrical device to a plurality of external electrical conductors so as to facilitate use of the electrical device in a number of different operating modes. More specifically, this invention relates to a programmable terminal strip for a wound and terminated stator of an electric motor which connects a plurality of internal phase windings to a plurality of external leads so as to facilitate use of the electric motor in a number of different operating modes.
Electric motors are well known electrical devices which convert electrical energy to rotary mechanical energy. To accomplish this, electric motors establish and control electromagnetic fields so as to cause the desired rotary mechanical motion. There are many different types of electric motors, each utilizing different means for establishing and controlling these electromagnetic fields. However, the two basic components of most conventional motors are (1) a stationary member which generates a rotating electromagnetic field, generally referred to as the stator, and (2) a rotatable member driven by the rotating magnetic field, generally referred to as the rotor.
In electric motors, as in many other diverse electrical devices, a plurality of internal electrical conductors are provided within the device which must be connected to a plurality of external electrical conductors in order for the device to operate. In the context of electric motors, a plurality of internal electrical conductors is provided within the motor. The internal electrical conductors are typically embodied as a plurality of phase windings on the stator of the motor. Similarly, a plurality of external electrical conductors is provided outside of the motor. The external electrical conductors are typically embodied as a plurality of leads connected to a source of electrical energy. To connect the internal electrical conductors to external electrical conductors and thereby permit operation of the motor, an interface structure is usually provided. The interface structure connects the source of electrical energy to the phase windings of the motor to permit operation thereof.
In some electric motors, the interface structure is a fixed terminal board which provides a secure but unchangeable connection between the internal and external electrical conductors. Although such fixed interface structures are relatively easy to manufacture and assemble, they suffer from the inability to change the connections between the internal and external electrical conductors to permit the motor to be operated in different operating modes. As a result, a plurality of relatively similar motors must be manufactured and inventoried to accommodate all of the different desired operating modes. This result is obviously uneconomical. To address this, it is also known in the art to provide a non-fixed terminal board connection between the internal and external electrical conductors of a motor. Unfortunately, known terminal boards which are changeable have been found to be relatively difficult to change between operating modes or relatively complicated or expensive. Accordingly, it would be desirable to provide an improved structure for a terminal board for an electric motor or other electrical device which permits the changing of operating modes easily and which is relatively simple and inexpensive in structure.